The invention relates generally to the field of modulating the chiller controls for an air-conditioning system, and more specifically relates to a chiller modulator system by which the chilled water of the chiller may be raised under given conditions thus saving energy.
Air-conditioning equipment manufacturers design their machinery to the requirements of a new building, that is the so-called "worst day" conditions. For example, a building in a hot climate must be maintained at 75.degree. F. temperature and 50% relative humidity condition inside even though the outside conditions may be 95.degree. F. and 75% relative humidity. In order to establish the desired conditions inside the building, the chilled water may be maintained at perhaps 42.degree. F. leaving the chiller. In general, the controls of the chiller are set to output a constant leaving chilled water temperature. Accordingly, it will be appreciated that energy is being wasted because space conditions may be cooler than needed. On days in which the demands on the chiller are moderate, it is possible to maintain a comfort level in the space with a higher temperature of the chilled water leaving the chiller. Obviously, it is not practical for an operator to be constantly resetting the chiller controls to affect energy savings to maintain a comfort level or zone within the space. The heretofore known prior art does not provide automatic monitoring of the conditions in the controlled space and does not automatically adjust the leaving chilled water temperature requirements of the chillers depending upon conditions in the controlled space.
Among the prior art which is of interest only with respect to the instant invention are the following U.S. patents. They are: U.S. Pat. Nos. 4,024,725; 4,018,584; 3,913,344; 3,834,617; and 3,738,609. None of the cited patents is particularly pertinent to the subject matter of this invention.